Spatial Cognition and Computation 2: 393–419, 2000.
© 2002 Kluwer Academic Publishers. Printed in the Netherlands.
A study of people’s sketching habits in GIS
ANDREAS D. BLASER
National Center for Geographic Information and Analysis, Department of Spatial
Information Science and Engineering, University of Maine, Orono, ME 04469-5711, USA
Received 13 November 2000; accepted 12 November 2001
Abstract. Sketching is traditionally associated with doodling simple strokes on a piece
of paper. Only few professionals outside of design and the ﬁne arts have recognized the
expressive power of this intuitive modality. However, sketching seems particularly well suited
to capture objects and situations in a spatial environment, such as geographic space. To learn
more about the techniques and strategies people use when sketching, a survey of sketching
was conducted. The study showed that paper and pencil sketches contain mostly simple and
abstract objects that are composed of only few strokes. The spatial conﬁguration of a scene is
primarily expressed through the topological ordering of objects relative to each other. Metric
relationships are used to reﬁne spatial conﬁgurations. These and other ﬁndings suggest that
sketching is an appropriate modality to interact with a computer where one wants to describe
and capture object conﬁgurations in a spatial environment, such as a geographic information
Key words: freehand sketching, human computer interaction, human subject testing, multi-
modal user interfaces, spatial querying, spatial information retrieval in GIS
Sketching has been used to visualize, record, and exchange information
for hundreds of years. Despite its proven expressiveness, sketching has not
yet become a frequently used modality to interact with computer systems.
Geographic information systems (GISs) have a particular need for such
advanced forms of user interaction, because they frequently involve complex
and heterogeneous data structures that are difﬁcult to describe when non-
visual tools and techniques are used. This paper is, therefore, primarily
concerned with sketches drawn in a geo-spatial environment.
Although sketching skills can differ considerably from one person to
another, it seems that most everybody is able to draw a sketch or under-
stand a sketched scene that was drawn by somebody else. The reason for
this common base of interpretation is possibly a set of reoccurring patterns,
symbols, or sketching strategies that people use when they are sketching.